The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
LIPA (local IP access) enables a UMTS or LTE device to access a local IP network that a femtocell is connected to. When a user has a femtocell at home or in the office, mobile devices may use LIPA to access devices that are connected to the local network over the femtocell. To get access to devices on a local network to which a femtocell is connected to, the mobile device uses a special APN. APN tells SGSN (UMTS) or MME (LTE) that the mobile device wants to get a connection to the local network and not to the network operator's core network. Optionally, a LIPA flag is defined that is sent by the mobile device during PDP context establishment (UMTS) or default bearer activation (LTE) for the same purpose. For simultaneous access to the local network and the internet, the mobile may have two PDP contexts (UMTS) or two default bearers (LTE): one that terminates in the local network and one that goes through the core network to GGSN/P-GW. In case internet connectivity is available through the local network, LIPA allows UE to reach the internet this way. Once the LIPA PDP context/default bearer is established, data flows directly to L-GW and from there into the local network without traversing the radio access network or the core network of the network operator. Control of the LIPA PDP context/default bearer may remain with SGSN/MME in the core network. In other words, authentication, authorization and security procedures remain with the network operator. Incoming packets from the local network are forwarded to a mobile device that is in an UMTS idle/cell or URA_PCH state or LTE idle state respectively. In these states, the mobile device is paged first and has to re-establish an RRC (radio resource control) connection before the data can be forwarded.